The invention relates to a discharge shaft for a bottom discharging vertical centrifuge with a filtration drum. Particularly, the invention relates to a vertical centrifuge, suited for separating a suspension into solids and a filtrate, which comprises at least one discharge shaft under the drum, in a base plate, in the vicinity of a hub of the drum.
The solids remaining in the drum of a vertical centrifuge following the separation process must be removed from the drum and the centrifuge separately from the filtrate. In conventional bottom discharging vertical centrifuges, a discharge shaft for the removal of solids is provided in a base plate located under the drum. In order to be removed from the centrifuge, the solid material may drop down the shaft, possibly after being scraped from the internal wall of the drum.
In the use of centrifuges in the pharmaceutical industry or in the food industry, it is essential that the centrifuge be kept clean. In particular, no solid residues must be permitted to accumulate in inaccessible grooves, recesses and corners of the centrifuge. The discharge shaft is particularly critical in this respect because it is only observable and accessible with difficulty from the manhole for cleaning purposes located in the upper cover plate of the centrifuge. The discharge shaft or shafts usually extend radially outward in the area around the hub of the drum, so that their horizontal cross-sections define an approximately annular region. This annular region is, however, not only occupied by the discharge shafts, but also by drive means (e.g., a V-belt drive) leading to the drive shaft of the drum. For reasons of keeping the inside of the centrifuge clean, the drive unit must be kept separate and sealed off from the discharge shafts.